People are social creatures. We meet, we greet, we network, we socialize. We also like to share information, be it news, gossip, business talk or anything else. When we first meet a new person, for instance, we may exchange contact information so that we can communicate later, such as by writing on the back of a napkin or other scrap paper. With people we already know, we may swap family photos, e-mails, or other similar items. And when we are working with electronic devices such as personal digital assistants (PDAs) or smartphones, we may simply beam such information back-and-forth using wireless communication protocols.
However, we don't always want to share such information with everyone in the area, and wireless communications spread out in every direction (absent a dish or other structure to direct them, or the ability of walls to block them, as with infra-red signals). As a result, users may e-mail information to each other when they meet so as to limit the ability of a third party to intercept such information. Other elaborate mechanisms may likewise be used to provide relatively secure communications between two wireless devices that are in proximity to each other (e.g., within feet or yards of each other and within a line of sight of each other).